<?php
/*
 * Plugin Name: Show Mail Customer
 * Description: This is...
 * Author: Phan Van Nhien
 * Plugin URI: namviet-it.com
 * Version 1.0
 */
?>
<?php
// Plugin Folder Path
if (!defined('SENDMAIL_PLUGIN_DIR')) {
    define('SENDMAIL_PLUGIN_DIR', plugin_dir_path(__FILE__));
}
//add menu
add_action('admin_menu', 'add_menu_mail');
function add_menu_mail() {
    add_menu_page('Email', 'Email', 'manage_options', 'email', 'show_email');
}

function show_email() {
    include SENDMAIL_PLUGIN_DIR.'show_email.php';
}
?>